According to KCAL 9's inverview with the Irvine police, you can tune in to radio station 1640 am for the latest info, and/or call the emergency hotline at 714-628-7085. The OCFA's site was last updated at 5:55 pm and much has burned since then. Also I heard that if evacuations were to be ordered, they have a phone system set up to telephone residents (although I don't know how this would work in practice considering cell phones, etc).
We are in Tustin Ranch, off Jamboree near Portola. I hear sirens as I am typing this. I have gotten a few things together in case we are evacuated. It's gotten me rattled but I'm trying to mellow out. Hope I don't have to meet any of you guys at any shelters!
BTW, this is my first post after lurking for a while.